Cavity QED effects with Quantum Dots in Semiconductor Microcavities
Matthew Rakher
University of California, Santa Barbara, US.
Abstract: Cavity quantum electrodynamic (CQED) effects are studied in semiconductor microcavities embedded with InGaAs quantum dots. Evidence of weak coupling in the form of lifetime enhancement (Purcell Effect) and inhibition is found in both oxide-apertured micropillars and photonic crystals. Very large single photon count rates are obtained from s-shell transitions of quantum dots in resonance with the high Q modes in the micropillar cavities. In combination with charge-tunability, these devices constitute a promising avenue for quantum communication protocols and quantum computation. Surprisingly, high efficiency, low-threshold lasing is observed in the photonic crystal cavities where only 2-4 quantum dots exist within the cavity mode volume and are not in general spectrally resonant. The transition to lasing in these soft-turn on devices is explored in a series of nanocavities by observing the change in photon statistics of the cavity mode with increasing pump power near the threshold.